Telephone-exchange system.



S. H. BROWNE. TELEPHONE EXGHANGB SYSTEM. ARPLIOATION FILED AUG. 29, 1004.

Patented Sept.23,1913.

2 SHEETS-SHEET 1.

s. H. BROWNE. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED AUG. 20, 1904. 1,073,589.

Patented Sept. 23, 1913.

2 SHEETS-SHEET z.

. board but even that has the disadvantage.

UNITED srarss PATENT curios.

SIDNEY HAND BROWNE, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATIQN OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

To all whom it may concern:

Be it known that I, SIDNEY HAND .BRowNE, a citizen of the United States of America, and resident of Pittsburgh, county of Allegheny, and State of Pennsylvania, have invented a new and useful Telephone- Exchange System, of which the following is a specification.

My invention relates to improvements in telephone exchange systems, and has for its service, the subscriber signifies his desire to be connected with another lineby removing h1s telephone receiver from its hook. This lights an incandescent lamp. or sets some otherform of visual signal fore a certain operator in the central office, notifying her that she must connect her telephone with his line, and by conversationascertain his desire, then connecting him with the line for which he calls. It is usual to provide each operator with a certain number of lines, from which she receives calls, and to give her access to all of the lines of the system directly, that she may connect the lines of her group of subscribers with them, or by means of a trunking system to give her similar access even though all the SllbSCIlbers lines do not appear before her. It is found that to give each operator a certain number of subscribers lines which she shall answer, does not enable her to maintain an even rate of working, because some subscribers make many more calls in a day than do others; inventions have been made enabling the number of lines terminating before a given operator, to be increased or diminished from time to time in order that the position of the switchboard served by one operator may not demand more of her than she can erform, or demand so little as :not to keep er busy. Such an ability to redistribute the lines is given by the device known as the intermediate distributing that it is only useful to make relatively permanent changes in the connections of the Specification of Letters Patent.

Application filed August 29, 1904. Serial No. 222,645.

Patented Sept. 23, 1913.

lines, and it has little usefulness unless the traiiic produced by the various lines, individually and in groups, be studied for a considerable time so that it may be guessed what traliic they will produce in the future, and redistribution made accordingly. The intermediate distributing board when used thus in the best way of which it is capable, will not even up the traffic in such a way that each operator will be evenly busy throughout all the hours she is working, but will only prevent great inequalities among the operators at a given time. For example, during the busy hours of the day, the traffic of the ofiice may be handled by a certain number of operators, each working to full capacity, and with practically identical loads for each; but in the less busy hours of the day the operators may be reduced in number, one of them serving two or three or more of the groups of lines served by an operator each during the busy hours; but at the best she can give prompt service only by serving such a group of lines as she can compels so small a number of operators as to give each of them a greater length of the switchboard to serve than she can handle without walking from one lace to another toanswer the calls, the quality of the service will suffer in that the calls will be answered less promptly.

My invention accomplishes the result of automatically distributing the calls upon the switchboard so that as many calls come to an operators position as she can reasonably well handle, and they come with a much greater steadiness than is true under the present systems. This enables the total traffic to be handled by a minimum number of operators, insures that each call can be plates, 23and 24, having the lugs, 40, 40, formed from them for conveniencein mount .same circuit relations as are there shown will be repeated when a number'of switches are connected to form a complete system. The

ing the switch, "are clamped together by the bolts, 38, and the nuts, 39. Contactpieces,

25, 26, 27and 28,25, 26*, 27" and-"28*, with others quite similar, are arranged in four horizontal'circular arcs between the plates 23 and 24; of these contact pieces, there are,

a number in each circular arc; in the form of switch which I showv in these figures, there:

are twenty-five contact piecesineach arc,

' and each pieceis brought out at the periphcry ofthecircular portion of the switch so that awiremay, beattached to it. Between each row ofcontact pieces and the neighboring-row, between the upper row and the'top plate, 24, and between the lower row and the bottom plate, 23,. -insulating material, 94,

-- such-as hardrubber or .fiber,jis clamped by the double-purposeof insulatingthe contact the bolts, 38, and the screws, 95. I This serves pieces from each other and from the framework, and holding all of them secnrely in position. v I

Plates, 24 and 23, have attached to them or formedfrom them respectivelythe bear ing studs, 17 and 29. These guide and sup :port the .vertical shaft, 30, which carries on tion, the pin, 22,- engages the post'16; the

itsfupperv end the ratchet wheel,f13, and which isadapted to be held in or returned to normal position by the action of the spiral spring, l4,'at tached to the shaft, 30, at one end, andtothe-pin, 15, at the other. The pin, 15, iscarried by the top plate, 24. When the ratchet wheel, 13, is in its normal posipin, 22, also engages thecontact spring 19,

ending it out of contact with the contact piece,-18.- The spring, '19, carrieson its end .aninsulation' to prevent electrical contact with the pin, 22." Spring, 19, and-the piece, (18, are ,separat'ed'from electrical: contact" w'ith each other and with the conducting suitable material; the by a screw, 21.,- bush'e partot' the switch structure,by tlieinsulate' rubber or ,other hound to jplacet I i in contact with. the spring and contact pi'ecein a familiar.-

ing pieces, 20, 20 and-"2 manner and entering the bracket, 12. .Thebracket, 12, serves the doub1eipurpose-;of.., :sup orting the; mugnet coils,'8 and 8, and of orming' apart of the magnetic circuit ofi qthose coils; one end of this bracket forms .a pivot with the arm, 10, adapted to form'a' itetaining pawl to? the ratchet wheel,-13.v

The helical spring, 11, is a 'retractile one, holding the pawl, 10, in engagement with 'a'tooth of the ratchet wheel, 13, unless the iron armature, 9, is sufficiently attracted by the'core's of the coils, 8 and 8 when they are energized. Of similar structure-is the magnet formed of the coils, 1 and 1*, the

bracket, 2, the iron armature, 4, and the lever, 3, except that the latter carries a further pivoted part, 5; a helical retractile spring, 'Z, tends not only normally to hold the arm and "armature,' 3 and 4 respectively, ,away from the cores ofthe coils, 1 and 1, but to keep the free end of the arm, 5, in engagement with the post, 6, carried by the top plate, 24; Unless the coils are energized, the tree tip of the arm, 5, will be out of engagement with the teeth of the ratchet wheel, '13; but if the coils are energized, attracting the armature, 4, the motion .of the arm, 5, will enable it, while still sliding in. contact wit-h the post, 6, to engageatooth of the ratchet wheel, 13*,and advance i'tone step; the wheel will then be held'b'y anew engagement of the pawl, '10, against a tooth,

the'tip'of the arm, '5, will again pass out of engagement with the ratchet wheel, 13,,and successive'impulses ofcurrent will advance the ratchet vwheelfstep by step, carrying with it the shaft, 30. Therelation between the teeth of the-ratchet wheel and thecontact pieces, 25,25, 25*, and the similar contact pieces inthe pther three rows, is such that for each, advance of the, ratchetwhe el onestep, the'contact wipers, 34,35, 36' and 37, will engage the different contact pieces of the rows successively the contactwipers, 34 to 37 inclusive, are in pairs, the -two.mem-

hers of eachpair being in electrical contact,"-

but each pair being insulated from the shaft and other conducting-parts of the structure by insulating bushings, 32, 33,adapted not only to bind and to space the'contact wipers, but to center themalsoin a well-known manner. The'endsof thec When the cores,. l and 1 are deenerglzed,

tact wipers which donot engage the contac pieces,'are adapted to receive flexible-conductors making cont nual connection with the contactwipers during a movement through the wholearc.

. The IlOI'mal position ofthecontact wipers is out, of engagement with any contact piece; one step, of the ratche't liv heeil, them to ma ke contact respec' ely with the first contact pieces injthtlfrows; and suc-v ce'ssivelyyimpulse. by impulse, "to the end of the arc. The a chiati n of" the -magnets,[8 ands, at any" as, will release the ratchet wheel, 13, unless the magnets, .11 and 1.,are also energized; upon "such release the contact wipers return to normal ,ppsition,out"of'engagement with any contact pieces, and the connection-between the spring, 19, and the contact piece, 18, is broken, although it had been made during 13, causes a all the time the contact wipers were not in their normal position.

Referring to Fig. 4, the line formed of conductors, 41 and 42, connects the subscribers instrument, 43', with the mechanism of the central offic The subscribers instrument is of a type adapted for use with central energy systems, and is one inwhich the" line circuit is open to direct current unless the receiver is off the switch hook. It will be seen that the subscribers line, in the central office, is associated witha number of electrical devices, and may be considered as a unit with the elements of a circuit broadly considered to terminate in the contact wipers, 34, 35, 36 and 37. Another group of devices may be considered as a unit, and as beginning in the drawing at the contact pieces, 25, 26, 27 and 28, (the numbers, fo-rclarness in the drawing, being located contiguous to wires connecting with those contact pieces), and extending to include the.plug 92. The drawing shows further at the right, a subscribers instrument and line, similar to that first mentioned, but from which the details not essential to this specification have been omitted.

Considering first the character and functions of the mechanism associated with the line, 41 and 42: It is provided with multiple jacks, three of which are shown in Fig. 4, each having the elements of two line springs and a test ring, respectively 47, 50 and 4.4; 48, 51 and 45; 49, 52 and 46. Similar springs in each jack are connected to one side of the line, and this istrue whatever may be the number of spring jacks required for each line in a given system. The test rings of all the jacks of a line are connected together and to the winding of the cutofl' relay, 55, the other end of that winding being connected to ground. Under normal conditions this relay is not energized, so that its armature, 56, will make contact with the grounded point, 58, and its armature, 57, will make contact with the point, 59, establishing thence a circuit from the line wire, 41, through the relay, 53, to another relay, 61, and the battery, the remaining pole of which is grounded; The relay, 53," is pre-,

ferred to, be shunted "by the non-inductive resistance, 54, so proportionedas to allow the relay to be operative through the proper margins of voltage andline resistance, and yet to enable voicecurrents to pass through the non-induct've resistance as well as through the i pedance. of the relay winding. A relay, 64, has its winding in a connection between the free pole of the battery and the contact wiper, 37. The normally ciosedcontact between its armature, 65." and point fiti -serves to maintain a circuit such that if the-"relay, 61, should be energized, closing its armature, 62, upon the point, 63,

7 its armature to break its backcontact.

make contact with the forward the interrupter, 200, kept constantly rotating at the proper rate, will serve to cause impulses of current through the path described, and the switch winding, 1; the switch winding, 1, is that which has been described with reference to Figs. 1, 2 and 3,

as adapted to, rotate the contact wipers, 34,

35, 36 and 37, and with the conditions which I have described, such rotation would be caused to begin immediately upon the subscribers removing histelephone receiver from the hook to makea call. It is my intention that this shall be the result, and that when such rotation beginsit shall con tinue through the arc of the subscribers rotary switch until, in makin -successive contacts, a position is found connecting the subscribers line with a set of four contact pieces leading into a plug-terminated circuit upon which, at that moment, no other subscribers line is connected. I have shown that each subscribers switch has many sets of four trunk contacts each; and these are as many points of access toplug-terminated trunks. I

In Fig. 4, I indicate the existence of a plurality of possible trunks to be selected, by showing not only the'contact pieces, 25, 26, 27 and 28 as onetrunk, but 25, 26, 27 and 8, as' illustrative of other trunks. During the period, therefore, which succeeds the removal of the subscribers receiver from its hook, the rotation will continue as long as the circuit through the magnet, 1, remains as first established. When in. the successive steps the contact wiper, 37, engages a contact, as 25, which is grounded through the back contact of the armature, 69, upon its point, 70, of the relay, 68, further rotation will be stopped because so finding a ground by the contact wip'er, 37, will energize the relay, 64, of the line, causiXg s this breaking prevents further rotative impulses, the switch will remain upon the contact pices of thatatrunk, selecting it as an extension of the subscribers line to the operators position 'upon which are located the trunk signals and other trunk mechanisms yet to be described. As a further result of the finding ofthe. grounded contact piece, 25, by the contact wiper, 37, the relay, 68, will be energized and its armature, 69, will oint, 7 1, and afterward will break the bacc contact with the point, 70. Simultaneously, also, the armature, 72, of the same relay will make contact with the point, 73, causing current from the battery to flow through the resistance, 96, the contact piece, 26, the contact wiper,'36, to and through the winding of the cut-off relay, 55, to ground. The cutoil relay, operating, will break the contact of its armature, 56, from ground and apply it to the conductor leading immediately to the contact wiper, 3 1; similarly it will break the contact of its armature, 57, from therelay, 61, and apply it to the. contact, 60, leading directly .to the contact: wiper, 35. The effect is to extend the line immediately through the contact wipers mentionedto the line conductors of t-hetrunk,.terminating in 'an operators position. A further .efl'ect is to release thep'reviously closed contact of" the relay, 61, preventing arenewed rotation .of the 'subscribersswitch which would otherwise occur 1 Theresistance 96 operates" to reduce the current from battery 87 through the cut-oft relay 55 to approximately such a volume as the cut-oil relay 55 would receive from a plug inserted .in one: of the .multiple jacks 4: 14:54:6, andthus to-give a busy test condition to the multiplejacks similar to the condition placed upon those jacks' by the insertion of a connecting plug in one ofthem.

' It will'be .notedial so that when the switch of arcalling-lin'e is connected temporarily,

with a busy trunk while passing thattrunkl 1n its .search for an idle trunk, the cut-off {relay associated With the seeking switch .is

placed in shunt wit-h the, cut-ofi relay as that, trunk busy; the resistance 96 in 30' plug. The subsc'ribers line nowbeing ex- 1 tended into the line conductors of the plug terminated trunk, the relay, 7 4,whose windingis bridged across the line conductors of the trunk, and in series 'with the battery,-

will be operated. On e of the e ffects is to close thearmature, 75,,11 on its ,contact 76, connecting. the, two win ingsot the relay,

68, in series with the battery and earth,',thus

holding it energized. The other armature, 77, of .the' relay, 74, leaves point, 78-, .and

engages point, 79, lighting the signal lamp,

86, because the back'contac't of the armature, 8 7, of the relay, 85, is closed. This lighting isa signal to the operator in charge of that trunlg that a callrequires to be answered; this she does, by actuating her listening key, 91, in the, usual manner, afterwhich, in conversation with the subscriber, she determines his wants, lifts the trunk plug, 92, tests the multiple jack of the called line, inserts the plug'in the jack if the line proves not to be busy, and rings the called subscribers hell by means of the ringing key, 97, or other .101, to connect. I I I H p 1 tween spring, 19, and pomt, 18,1oifthe ro-' tary switch, had beeir'inade s nce the, first equivalent mechanism, such as an automatic arran emen't for establishing conditions to ring is bell until he responds.-

- The act of inserting the trunk plug, 92, in

the jack of theline of a calledvsubscriber,

not only connects the calling and the called" lines in' re'adiness for talkingwhenthe called subscriber answers-but connects the battery the sleeve, 9%, of the plug through the test ring of the jack-with the winding of the cut-oil relay, 98,.belo-nging to that line, and I through the winding of;the'relay; 85, and

through that winding to ground. Thus the i cut-oil relay, 98, is operated; disconnecting thecalled line'from connection with its own:

rotary switchand associated relays, so that the'fanswering, of the called subscriber will not-cause-any operation of those parts of the equipment of his line in the-central ofiice; The relay, 85, also opeiatesbreaking the contact between'one. of its armatures, 87,

and its back contact,' 88, and extingulshes the signal lamp which caused the operator ,to answer'in the-first place; the armature,

87, closes on its front contact, 99, remaining there during all the time the trunk plug is in connection; the armature, 89, of the relay, 8'5, closes on its front contact, 90,-:lighting the signal lamp, 83, through. the connection between the back contact, 82, andara mature, 81, of the relay,.8 -.When the called subscriber answers, removing his receiver from its hook, therelay,80, is energized.

Its winding is bridged across the line at a point between the condensers, 8 4, 84, and the inner contacts of the ringing. key, 97 and is also in series withthe battery. .Thearmature, 81, thus loses contact with .the point, 1' i 82; lamp, 83, is extinguished, notifiyingthew'. I operator that further ringing on heipart is,

unnecessary. It is obvious that if the ring-Q ing key, 97, were an automatic one, ringing o until the subscriber should answer, this 'functienof the lamp, 83, would, be unneces. sary, and such an arrangement of, my'cir cuit might be made with advantage. Q'Under the conditions which vI have described, cone;

scribersversation mayprogress between the two sub- 1 At the closeof the conversation, the hauga ,ing up of his receiver by the calling Sub;"

scriber, permits the relay, 53, tode'e'n'ergize,

allowing its armature, 100, and backlcontact,

vBecause the ;contact be,

step of the mechanism, t-liis falling. away of .the armature-of. the relay, 53, occurring for the firsttime since the beginning of the en-fl the cycle of .events will cause the battery to energize thewindings, 8, of. the release magnets. The pawl, 10, drawing out of the ratchet wheel, 13, will allow the switch to,

ing contactbetweenspring, 19, and contact, 18. It is, thus evidentth-at the hanging up returnto its normal position, again breakof the telephone of the calling subscriber at the close of the conversation, accomplishes immediate disconnection, and that upon again removing his receiver from the hook,

the rotation of the switch 'will be repeated.

Because of the immediate release of the rotary switch and its return to a normal position, the relay, 74, will be deenergized;

because the trunk plug is still in position tion is desired, which act she then performs.

The hanging up of the telephone on the part of the called subscriber, will release the re-' lay, 80, closing its back contact, and relighting the signal lamp, 83, also serving as a disconnect signal to the operator in case she had not already obeyed the previous signal due to the disconnection of the rotary, switch.

The described result of immediate disconnection upon pulling down the hook at the calling station, gives further clearness to my statement that the operation of my system; accomplishes an improvement in the quality of the service due to speed. It is evident that a subscriber, concluding a conversation, and desiring another connection, has only to hang up his receiver for an instant, or what is equivalent, pull down the hook and let it up again, whereupon his r0- tary switch will lmmediately select anotheridle trunk.

Inasmuch as the equipment of each subscribers line includes in the central oflice not only the mechanism of the rotary switch and the relays associated with it. but also a series of multiple jacks distributed before the operators, it is necessary that busy test features be provided for. I show in Fig. 4 that the operators telephone is adapted to such a busy test, and that it will be received whenever there is existent at the test rings of the spring jacks a difference of potential with relation to the earth. There are two ways whereby this busy test potential is placed upon the test rings; one is the result of the existence of the trunk plug in one of the jacks of the line, and the other is a result of the selection of the trunk on the part of the rotary switch of the line. Thesame circuit conditions which caused the operation of the cut-off relay of the calling line immediately after the selection of an idle trunk, impressed a potential upon the test ,rings, 44, 45 and 4G, and this potential is maintained until the subscriber hangs up his receiver; It thus will be seen that the line of the calling subscriber is guarded from interruption from the instant his rotary switch has selected the trunk, and that the line is not left unguarded during any portion of the interval of waiting for the operator to answer after the lighting of the signal lamp.

In the practical arrangement of the various subscribers switches with relation to the trunks to the operators, I prefer to terminate in each operators position such a number of trunks as when continuously occupied by successive conversations, will furnish an amount of work which the operatorcan just successfully perform. The nuinber of these trunks per position depends upon the length of time of the average conversation, as well as upon the ability of the operators, but probably will be approximately ten.

The rotary switch for each subscribers line has twenty-five sets of stationary contacts, according to the structure shown in Figs. 1, 2 and 3. Each of these twenty-five sets of contacts forms a terminal for a trunk line, as shown clearly in Fig. 4; and in order to give a number of subscribers lines access to the same trunkflline, I multiple the trunk lines through the corresponding Sta-- tionary contact points on the rotary switches in much the same manner as is followed in the ordinary multiple switchboard of modern practice, whereina suhscrihers line is multipled to a separate jack on every section of the switchboard. Each rotary switch will thus afford the subscriber to which it belongs, access to twenty-five trunk lines, if the switches are constructed as here shown. Of course each switch may be made to afford access to a greater or less number of trunks if desired, by giving each rotary switch a greater or less number of contacts.

\V here there is such a number of subscribers lines as would require, at the time of maximum traflic, a greater number of trunk lines than there are contacts upon any switch, it would become necessary to divide the subscribers lines into groups, there being as many lines in each group as would be likely to keep busy, at the time of maximum trafiic; the number of trunk lines for which terminals are afforded on each switch. To make this clear, if the switches used have twentyfive sets of contacts each, and if there were centered in the ollice as manysubscribcrs lines as would require the use of say fifty trunks, then the subscribers lines would be divided into two groups, each group being served by twenty-five trunks. All of the corresponding contacts on the switches of any one group would be multipled together and connected to the wires of one trunk line, as has already been pointed out.

The movable contacts on the selecting switch may properly be termed selecting such as.25, 26, 27 and. 28,;may be'ter'med' selecting contacts.

limited in allcases; to anyparticnlar form rangementof circuits here shown, as j many" I modifications? might be made therein: wit-11+ T lines, multiple jacksfor said telephone lines scribers lines, multiple connection terminals waiting cont-acts for-each switch, thecorre contacts since they are actively involved in establishing a connection between a line and.

.form of mechanically-actuated flexible-terof m. invention. Neither do I wish'tjo- -limit i of a telephone line, a" pluralityofi multiple 1 .jacks ltherefor, a rotary 'selective" switclifor} v said line, selecting contacts for jsaidyswiteli" f.

that is not in use, and means' for connecting -when' said contacts en a'ge the Waiting c0n-.

- scribed.

' each of saidlines, selecting contacts for each to a trunk. Similarly the stationary contacts,

waiting vcontacts;"?,*since-'they. areaassive and remain imposition to be engaged by-the These' waiting contacts may also be" termed; multiple contactsffiQ since the corresponding contacts I on j the switches. of a oup of'lines '-are-multipledtogether in a sunilar manner, to the multi-' a 'pling of the jack contacts in a' multiple board. I 1

5 The movable parts of the selecting switch form what may be termed aflexible terminal for a line, and I do not wish to be of flexible terminal, as I- believe that any minal, or selecting switch, whethermoving in a circular or 'straight path,and-whether moved a step at a time, orqby steady and continuous movement-will, if used forthe purposes herein outlined, liewithin the scope Inyse f in all respects to the exact construetion of otherv apparatus, nor to theexact*ar-- q t pa t i seir m, he-S iri t1on." a Havinglthus described myinventiomwhat '7 1. In a telephone combination normally disconnected from said line, a -pl1i-' rality of waiting contactsadapted' to been-- gaged 'by said'selectingcontacts, a series of trunk lines terminating-insaid waiting. contacts and in a switchboard,other telephone located in said switchboard, switching means for. connectingsaid trunks to said} lines, means for causing said selecting switch to automatically move saidselectingcontacts into engagement with the waiting; contacts'of the first trunk line of the series said selecting contacts: to said telephone line tacts of said-idle trun ,fsubstanti'allyas de-1 2'. In a telephonesystem, a group ,of sub-- for each'of said lines, a selective switchfor selective switch normally disconnected from the line to which the switch corresponds,

sponding waiting contacts ;on each switch being multipled together throughout the group of switches, a trunk lme for. ea hset travels-over jsaid' waiting contacts and for 4 n' cant a ofmultipled waiting contacts, said; lines terminatingeach in its di tant end in means adapted to connect that trunk line to a selected one of the telephone lines in ,o;

group, means forgcausing said selecting contacts to automatically select and connect with the waiting contacts of the first idle trunk, and means for connecting said select [:1 ing contacts to their-substation lines when sa1d contactsengage the waiting contacts of 5 an idle'trunk, substantially as described; In a'ftelephone system, aoup of-subgs scribers lines," a switchboard, multiple -j acks forv each of said lines and located in said for eachset of multipled; waiting contacts and extending to said switchboard,,means fo'rj starting said selecting contact-s 'in their continuingsaid travel over the waiting con tactsaoftrunks that'are atithetime connect i ed to' at other switches, means for arresting; vel {bfr said selecting contacts f u'pon} ing ontacts to saidsiibscribersline when I v otidfidle trunk are; n a endm as.'

were wa selected line',""subst tially as described.

waiting contacts for said selecting switch, trunk lines leading from'said waiting contacts to said switchboard,imeans outside of said switch for rendering some of said trunk lines busy, means for automatically moving said selecting contacts over the waiting-contacts 'ofsaid busy trunks, while" said selecting contacts are "disconnected'from said subscribers line, other telephone lines, multi-ple' jacks in said switchboard pertaining to said telephone line, multiple. jacks in said switchboard pertaining to said other telephone-lines, and-connecting means in said switchboard whereby any trunk maybe con- :nected to a multiple jack of'a selected line,

substantially as described.

In a telephone system, a switchboard, a

subscribers telephone line, a selective switch for said line, selecting contacts for said switch normally disconnected from'said line,

trunk linesleading from said walting contacts-to said switchboard, means outslde of said switch for rendering some of said trunk lines busy, means for automatically moving 130 inagmeans foficonnecting said seleet In: a telephone system, a switchboard, a V r1ber-"s-- telephone line,'a' selective switch p, for saidline,"selecting contacts for said switch normally disconnected from said line,

waiting contacts for said selecting switch,"

- ing contactson the waiting contacts of the first idle trunk and simultaneously connectmg said selectingjcontacts with said subscribers line, otherjtelephone lines, multiplejacks for said telephone line in said switchboard, multiple "jacks 'for said other telephone linesin said switchboard, and plugsforming terminals for said trunks and adapted to connect with a multiple jack of a selected one of said telephone lines, substantially as described.

6,. Ina subscribers telephone line, a selective switch associated therewith, a multiple switchboard having a plurality of operators positions, selecting contacts for said selective switch normally disconnected from said line, stationary contacts for said selective switch, a series of trunk lines leading from said stationary contacts to several of the positions on said multiple switchboard, means for causing said selective switch to automatically move said selecting contacts into engagement with the stationary contacts of the first idle trunk line of said series and means for simultaneously connecting said selecting contacts with said subscribers lines, substantially as described.

7. In atelephone system, a subscribers line, a selective switch associated therewith, a multiple switchboard having a plurality of operators positions, selec'tmg contacts for said selective switch normally disconn said selective switch, a series of trunk lines leading from said trunk contacts to several of the positions on said multiple switchboard, Ineans under the control of the sub- 1 scriber for causing said selecting contacts to engage the trunk contacts of the first idle trunk of said series, and means for automatically connecting said selecting contacts with said subscribers line, substantially as described.

8. In a telephone system, a subscribers line, a multiple switchboard in which said subscribers line terminates, a selecting switch for said line, movable contacts upon said switch normally disconnected from said line, stationary contacts ,for said selecting switch, means under the control of the subscribers line for causing said movable contacts to engage certain of said stationary contacts and to simultaneously connect said line to said selecting contacts, other subscribers lines terminating in said multiple .d from said line, trunk contacts on switchboard, trunks extending from said stationary contacts to said multiple'switchboard, and switching means in said switch- .board whereby any trunk may be connected with any line, substantially as described.

9. In a telephone system, subscribers telephonelines, multiple jacks for each of, said lines, a selecting switch for each of said lines, selecting contacts for each switch pertaining to one subscribers line only but normally disconnected from the line, wait ing contacts for said selecting switch pertaining to a plurality of trunk lines leading from said switch, means for moving said selecting contacts over the said waiting contacts of said selecting switch, means for stopping said selecting contacts in contact with the waiting contacts pertaining to a trunk not then in use, busy test circuit for said line, busy test circuit for said trunk, and means by which immediately after said selecting contacts stop upon said waiting trunk contacts, said selecting contacts are connected to said line, said line is made to give a busy test signal to any trunk seeking to connect therewith at any of the multiple jacks, and said trunk is made to give a busy test signal to any line seeking to connect therewith at any other of its waiting multiplE contacts in any other selective switch, substantially as described.

10. In a telephone system, a switchboard, a telephone line, a plurality of multiple jacks therefor located in said switchboard, a selecting switch for said line, selecting contacts for said switch normally disconnected from said line, a plurality of waiting contacts adapted to be engaged by said selecting contacts, aseries of trunk lines terminating in said waiting contacts, means for causing said selecting switch to automatically move said selecting contacts into engagement with the waiting contacts of the first trunk line of the series that is not in use, means for connecting said selecting" contacts to said telephone line when said contacts engage the waiting contacts of said idle trunk, other lines terminating in said switchboard, and signaling and switching means in said switchboard whereby any trunk may be connected to any line in said switchboard.

Signed by me at Pittsburgh, county of Allegheny, State of Pennsylvania, in the presence of two witnesses.

SIDNEY HAND BROl/VN E.

Witnesses:

A. H. MORAWECK, E. W. HATFIELD.

' Copies 01 this patent may be obtained for five cents each, by addressing the "Commissioner of Patents,

- Washington, D. O." 

